Module 3 CV Slides-UPDATED PDF

Cardiovascular Disorders 1  Lecture Overview Sections: 1. Normal anatomy and physiology- “A little refresher” 2. Hypertension and Hyperlipidemia 3. Atherosclerosis- risk factors, pathophysiology 4. Coronary Atherosclerosis- clinical presentation,...

Cardiovascular Disorders 1  Lecture Overview Sections: 1. Normal anatomy and physiology- “A little refresher” 2. Hypertension and Hyperlipidemia 3. Atherosclerosis- risk factors, pathophysiology 4. Coronary Atherosclerosis- clinical presentation, pathophysiology 5. Heart failure- clinical presentation and pathophysiology 2 Normal anatomy and physiology- A little “refresher” 3  Objectives Provide an anatomy and physiology “refresher” that will facilitate the learning objectives in this module. Topics include: The circulatory system The heart- mechanical, electrical, and ‘plumbing’ components Regulation of cardiac output Regulation of blood pressure and flow 4  The Circulatory System Diagram of the Pulmonary and Systemic Circulatory Systems and Flow Chart of the Direction of Blood Flow Veins Carry blood to the heart Typically carry de-oxygenated blood. Pulmonary Vein- contains oxygenated blood Arteries Carry blood away from the heart Typically carry oxygenated blood Pulmonary Artery- contained de-oxygenated blood 5 , Adapted from Patton KT, Thibodeau GA. The human body in health & disease, 7th edition. St. Louis: Mosby; 2018.)  Circulation through the heart Diastole refers to the time in the cardiac cycle that represents filling of the blood into a chamber of the heart. Systole refers to the time in the cardiac cycle that represents the ejection of blood from a chamber of the heart (e.g., contraction) Valves open and close to help keep the blood moving forward through the heart From Patton KT, Thibodeau GA. Structure & function of the body, 15th edition. St. Louis: Elsevier; 6 2016.  Heart Valves 4 valves: Right side: Tricuspid and pulmonic valves Left side: Mitral and Aortic valves During ventricular diastole what valves are open and what valves are closed? Left ventricle During ventricular systole-what valves are open and what Right ventricle valves are closed? Patton KT, Thibodeau GA. Structure & function of the body, 15th edition. St. Louis: Elsevier; 2016.) 7  Valve problems- some examples Stenotic Valve-the valve Leaky (regurgitant) valve- doesn’t open fully it doesn’t close tightly. 8 The Wall of the Heart The three layers of the heart wall—the epicardium, myocardium, and endocardium—are enclosed in a double-walled membranous sac, the pericardium. The pericardial sac has several functions: provides stability of the heart within the thorax, reduces friction between the heart and the mediastinal structures, limits the size of the heart chambers, provides a barrier to the spread of infection, and it contains pain receptors and mechanoreceptors that can cause reflex changes in blood pressure and heart rate. The thickest layer of the heart wall, the 9 myocardium, is composed of cardiac muscle  The Electrical System of the Heart An arrythmia is the term used when there is abnormal heart rate or conduction of the electrical impulse through the heart. Some common terms: Normal Sinus Rhythm: the heart rate is between 60-100 beats/minute and is generated from the SA node Tachycardiac- heart rate >100/min Bradycardia- heart rate 55%) Muscle too thick “Weak heart” “Stiff heart “ EF ≤ 40% EF ≥50% Heart can’t squeeze enough blood Heart can’t relax or fill with enough Normal ejection out of the heart with each beat blood between heart beats fraction: >55% “Heart failure with reduced EF” “Heart failure with preserved EF” (HFrEF) (HFpEF) The ‘middle child’ of Ejection Fraction https://www2.gov.bc.ca/gov/content/health/practitioner-professional-resou rces/bc-guidelines/heart-failure-chronic#fig1 91  Risk factors for heart failure Coronary Artery Hypertension Diabetes Disease Valvular Heart Smoking Family History Disease Excessive Viral Chemotherapy Alcohol Use Idiopathic 92 https://heartlife.ca/  Common symptoms of heart failure Shortness of breath Fatigue Swelling Orthopnea Paroxysmal Nocturnal Dyspnea (PND) 93  Atypical symptoms of heart failure Cognitive impairment* Delirium* Nausea* Abdominal discomfort Nocturia Oliguria Anorexia * May be more common presentation in elderly patients. 94  Right Versus Left sided Heart Failure Right Left Jugular venous Dyspnea, distension Orthopnea, Peripheral Cough edema Oliguria Gut edema- liver Pulmonary congestion edema 95 Heart failure with preserved ejection- a ‘stiff heart muscle’ Elevated pressure is needed for blood to flow into the left ventricle during diastole. In other works, left ventricular filling pressure is increased – Due to decreased ability of cardiac myocytes to relax and/or a decrease in left ventricle compliance Ventricular filling becomes impaired due to ‘high filling pressures’, blood is backed up into left atrium and pulmonary circulation- contributing to shortness of breath Elevated blood pressure and/or increased heart rate often aggravate the situation. HF with preserved EF: LVEF ≥50% (‘HF-pEF’) http://www.health.harvard.edu/newsletters/Harvard_Womens_Health_Watch/2008/September/Heart_f 96 ailure_in_women  Heart Failure with reduced ejection fraction- a ‘weak’ heart muscle Systolic Heart Failure “Weak heart” EF ≤ 40% Cardiomyopathy Impaired contraction due to a weakened heart muscle from: Myocardial cell death or damage Post MI remodelling “Heart failure with reduced EF” (HFrEF) EF ≤ 40% http://www.health.harvard.edu/newsletters/Harvard_Womens_Health_Watch/2008/September/Heart_f 97 ailure_in_women Cardiac Output and a ‘stiff heart’ HF with preserved EF- Reduced cardiac output due to filling problem (e.g. not enough preload or blood in the ventricle at the end of diastole) Increased afterload (e.g. hypertension) will aggravate the situation as it makes the heart work even harder. An elevated heart rate (e.g. >100 beats per minute) will also aggravate the situation as it decreases time for ventricular filling. 98 Cardiac Output and a ‘weak heart’ HF with reduced ejection is primarily a contractility problem. The body ‘s reaction is to increase preload and heart rate to try and increase cardiac output, but this is not sustainable and just wears out the failing heart muscle even more. In response to the decreased cardiac output, the body also tries to compensate – but this just tires out the heart over time and weakens the heart further. 99  ‘Compensatory’ Responses to Left Heart Failure Diagram shows how body tries to compensate for the reduced contractility due to MI and other dysfunctions. The reduced cardiac output means reduced flow to kidneys which activates the RAAS, raising blood pressure and so increasing afterload. Cells enlarge to try and respond and pump harder but that impairs contractility further. Vasoconstriction due to catecholamines (activation of SNS because lowered blood pressure sensed by baroreceptors) further increases afterload and ventricular remodeling. 100  ‘Compensatory’ Responses to Left Heart Failure Targets for pharmacological therapy in heart failure that help improve symptoms, quality of life and decrease mortality In some cases, patients will experience ‘reverse remodelling’ and an improvement in their ejection fraction Note- diuretics (or water pills) just “clean up the mess” from fluid retention- they do not have any effect on altering the pathophysiology associated with heart failure. 101  Naturetic Peptides- a newer target for heart failure Naturetic Peptides Sympathetic Nervous System Vasodilation Increase: Naturesis Heart rate Decrease SNS Blood pressure Decrease fibrosis Contractility Renin-Angiotensin-Aldostero ne System (RAAS) Help improve HF Vasoconstriction Kidneys- save water symptoms Fibrosis and heart function HF with reduced EF : LVEF ≤ 40% (‘HF-rEF’) 102  Increase levels of naturetic peptides Wall tension and strain **Neprilysin Naturetic NP release Breaks down Peptides naturetic peptides ** Ne prilys in Inactive fragments Vasodilation Naturesis Help improve HF Decrease SNS symptoms Decrease and heart function fibrosis 103  Increase levels of naturetic peptides Wall tension and strain Neprilysin Breaks down Naturetic NP release naturetic peptides Peptides Nepr ilysin Sacubitril- X Inactive fragments Neprilysin Inhibitor New medication: Vasodilation Sacubitril- Naturesis Help improve HF Neprilysin Inhibitor Decrease SNS symptoms + Decrease and heart function fibrosis ARB- Valsartan 104  Summary Heart failure is a chronic condition where the heart is unable to pump enough blood to meet the metabolic demands of the body. The most common risk factors for HF include CAD, hypertension and diabetes The most common symptoms of HF include shortness of breath, fatigue and/or swelling Signs and symptoms can be described in the context of right or left sided heart failure The ejection fraction (EF) is the % of blood pumped out with each beat – HF with an EF ≤ 40% is considered a ‘weak heart’ or systolic dysfunction 105 – HF with an EF> 40% is considered a ‘stiff heart’ or a filling problem There is no relationship between the severity of symptoms and ejection fraction. 106